The goal of this Award is to support Dr. Dane Chetkovich in his career as an independent physician-scientist. The candidate will continue his studies on glutamate receptor (GluR) synaptic clustering, a project he initiated under the mentorship of Dr. David Bredt at the University of California, San Francisco and has continued in his own laboratory at Northwestern University. GluRs are proteins responsible for most of the excitatory communication in the brain. Changes in neuronal communication efficiency are mediated by changing the number or properties of GluRs at synapses, and underlie aspects of learning and memory. Additionally, GluRs are implicated in the pathophysiology of many diseases, including Alzheimer's disease. Stargazin is a GluR-binding protein that is mutated in the epileptic and ataxic stargazer mice. In the stargazer mouse brain, GluR is made normally, but it does not target to synapses. Dr. Chetkovich's prior work demonstrated that stargazin delivery of GluRs to synapses is dependent on several parts of stargazin that interact with other proteins, including a protein known as nPIST (neuronal Protein interacting Specifically with TC10). This binding occurs at a region of stargazin that is critical for proper GluR targeting to the synapse. To further explore the role of nPIST in GluR targeting to the synapse, Dr. Chetkovich will use cellular biological, biochemical and electrophysiological approaches to test the hypothesis that nPIST chaperones the targeting of GluR receptors to the synapse by delivering the nPIST/stargazin/GluR receptor complex to synaptic scaffolding proteins, and that phosphorylation of the nPIST domain regulates this process. The Specific Aims of the proposed project are: 1) To understand the role of nPISTPDZ domain interactions in GluR synaptic clustering;2) To explore the role of nPIST phosphorylation in GluR synaptic clustering;and 3) To evaluate stargazin family member interactions with nPIST and GluR subunits in GluR synaptic clustering. These experiments will enhance understanding of the basic mechanism of GluR targeting to synapses, and should provide new insight into mechanisms by which abnormal GluR targeting contributes to neurological disease. These studies will hopefully lead to discoveries that identify novel targets for the development of treatments to fight disabling neurological diseases such as Alzheimer's disease. In addition to the project's goal of scientific progress in an area important to human disease, the K02 will allow Dr. Chetkovich protected and structured research time to continue his work at the bench and mentor his trainees and interact with scientific colleagues as he develops his scientific career. Northwestern University offers an outstanding environment for these studies, and the Department of Neurology has committed the resources for Dr. Chetkovich to succeed as an independent physician-scientist. It is anticipated that Dr. Chetkovich's progress, fostered by this award and the dynamic and supportive environment of Northwestern University, will enable successful competition for R01 mechanism and other funding to further sustain his career development and scientific efforts.